Ultrasound of the adult hip

Postoperative Fluid Collections in Total Joint Arthroplasty: A Narrative Review

A post-operative fluid collection (POFC) represents a common finding in both primary and revision total joint arthroplasty (TJA). Fortunately, most resolve on their own, but in instances where they become symptomatic, prompt identification and management are paramount, especially when they occur adjacent to a joint arthroplasty because of the increased the risk of developing a periprosthetic joint infection. A strong clinical suspicion with appropriate clinical exam is required along with select imaging modalities to arrive at a diagnosis. Meticulous surgical technique is crucial to prevent POFC, but new emerging treatments continue to evolve. This article presents an updated overview of incidence, pathophysiology, diagnosis, and management of POFC in the setting of TJA. We review the role of select imaging modalities as well as summarize current literature regarding new treatments such as sclerotherapy agents, acellular dermal matrices, and negative pressure wound therapy. Future studies are necessary to explore the interplay of inflammatory mediators in POFC formation and to define their role in fluid collection resolution.

Osteochondromas: An Updated Review of Epidemiology, Pathogenesis, Clinical Presentation, Radiological Features and Treatment Options

Osteochondroma, the most common benign bone tumor, is a projection on the external surface of the bone, which can be sessile or pedunculated. 85% of osteochondromas present as solitary lesions, while 15% occur in the context of hereditary multiple exostoses (HME), a genetic disorder that is inherited in an autosomal dominant manner. Although often asymptomatic, symptoms may eventuate from compression of adjacent vessels or nerves, fractures, osseous deformities, bursa formation, or malignant transformation. Cartilage cap thickness >2 cm in adults or >3 cm in children as well as new onset of pain or growth, or rapid growth of the lesion, especially after the closure of the growth plate, might reflect cancerous transformation. Surgical resection is indicated for symptomatic lesions, complications, cosmetic reasons or malignant transformation. Excision of the tumor with free margin is the treatment of choice. Local recurrence is less than 2% if complete resection is achieved.

The 2017 EULAR standardised procedures for ultrasound imaging in rheumatology

BACKGROUND

In 2001, the European League Against Rheumatism developed and disseminated the first guidelines for musculoskeletal (MS) ultrasound (US) in rheumatology. Fifteen years later, the dramatic expansion of new data on MSUS in the literature coupled with technological developments in US imaging has necessitated an update of these guidelines.

OBJECTIVES

To update the existing MSUS guidelines in rheumatology as well as to extend their scope to other anatomic structures relevant for rheumatology.

METHODS

The project consisted of the following steps: (1) a systematic literature review of MSUS evaluable structures; (2) a Delphi survey among rheumatologist and radiologist experts in MSUS to select MS and non-MS anatomic structures evaluable by US that are relevant to rheumatology, to select abnormalities evaluable by US and to prioritise these pathologies for rheumatology and (3) a nominal group technique to achieve consensus on the US scanning procedures and to produce an electronic illustrated manual (ie, App of these procedures).

RESULTS

Structures from nine MS and non-MS areas (ie, shoulder, elbow, wrist and hand, hip, knee, ankle and foot, peripheral nerves, salivary glands and vessels) were selected for MSUS in rheumatic and musculoskeletal diseases (RMD) and their detailed scanning procedures (ie, patient position, probe placement, scanning method and bony/other landmarks) were used to produce the App. In addition, US evaluable abnormalities present in RMD for each anatomic structure and their relevance for rheumatology were agreed on by the MSUS experts.

CONCLUSIONS

This task force has produced a consensus-based comprehensive and practical framework on standardised procedures for MSUS imaging in rheumatology.

Sonography of sports injuries of the hip

CONTEXT

Sports-related injuries of the hip are a common complaint of both competitive and recreational athletes of all ages. The anatomic and biomechanical complexity of the hip region often cause diagnostic uncertainty for the clinicians evaluating these injuries. Therefore, obtaining additional diagnostic information is often crucial for providing injured athletes with a prompt and accurate diagnosis so they can return to activity as soon as possible. Musculoskeletal ultrasound is becoming increasingly important in evaluating and treating sports-related injuries of the hip.

EVIDENCE ACQUISITION

The PubMed database was searched in May of 2013 for English-language articles pertaining to sonography of sports injuries of the hip using the following keywords in various combinations: musculoskeletal, ultrasound, hip, hip sonography, and sports.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Musculoskeletal ultrasound is currently being used for both diagnosis and treatment in a wide range of acute and chronic conditions affecting the hip, including tendinosis, tendon/muscle strains, ligamentous sprains, enthesopathies, growth plate injuries, fractures, bursitis, effusions, synovitis, labral tears, and snapping hip. Therapeutically, it is used to guide injections, aspirations, and biopsies.

CONCLUSION

Musculoskeletal ultrasound use is expanding and will likely continue to do so as more clinicians realize its capabilities. Characteristics, including accessibility, portability, noninvasiveness, dynamic examination, power Doppler examination, and low cost highlight the potential of ultrasound.

Practical approach to hip pain

Hip pain is a common complaint among patients presenting to outpatient clinics. Stratifying patients based on age, acuity, and location of pain (extra-articular vs intra-articular) can help to aid in appropriate imaging and timely referral to an orthopedic surgeon. A thorough history and an organized physical examination combined with radiographs are usually sufficient to diagnose most hip complaints. If the diagnosis remains uncertain, magnetic resonance imaging, usually with intra-articular gadolinium, is the imaging modality of choice in diagnosing both intra-articular and extra-articular pathologies.

Sonographic examination of the buttock

The buttock is a common site of pathology and ultrasound and is often the first-line imaging modality to examine soft tissue lesions of the buttock region. This review describes the ultrasound technique used, the relevant ultrasound anatomy, and the sonographic appearances of common and uncommon pathological conditions found in the buttock region.

Imaging of the hip in patients with rheumatic disorders

Hip joint abnormalities are commonly encountered in patients with rheumatic disorders. Although conventional radiography remains the mainstay for diagnosis of joint damage and subsequent follow-up, magnetic resonance imaging and, to a lesser extent, ultrasound have afforded the ability to detect early signs of articular involvement (i.e., synovitis and bone erosions), and to assess disease activity in treated patients. In more advanced stages of rheumatic disorders, magnetic resonance imaging and ultrasound are both useful in assessing paraarticular involvement (i.e., bursitis and synovial cysts).

Non-infectious ischiogluteal bursitis: MRI findings

Objective

We wished to report on the MRI findings of non-infectious ischiogluteal bursitis.

Materials and Methods

The MRI findings of 17 confirmed cases of non-infectious ischiogluteal bursitis were analyzed: four out of the 17 cases were confirmed with surgery, and the remaining 13 cases were confirmed with MRI plus the clinical data.

Results

The enlarged bursae were located deep to the gluteus muscles and postero-inferior to the ischial tuberosity. The superior ends of the bursal sacs abutted to the infero-medial aspect of the ischial tuberosity. The signal intensity within the enlarged bursa on T1-weighted image (WI) was hypo-intense in three cases (3/17, 17.6%), iso-intense in 10 cases (10/17, 58.9%), and hyper-intense in four cases (4/17, 23.5%) in comparison to that of surrounding muscles. The bursal sac appeared homogeneous in 13 patients (13/17, 76.5%) and heterogeneous in the remaining four patients (4/17, 23.5%) on T1-WI. On T2-WI, the bursa was hyper-intense in all cases (17/17, 100%); it was heterogeneous in 10 cases and homogeneous in seven cases. The heterogeneity was variable depending on the degree of the blood-fluid levels and the septae within the bursae. With contrast enhancement, the inner wall of the bursae was smooth (5/17 cases), and irregular (12/17 cases) because of the synovial proliferation and septation.

Conclusion

Ischiogluteal bursitis can be diagnosed with MRI by its characteristic location and cystic appearance.

Ultrasonography of the lower extremity

Ultrasonography is a useful imaging tool for various soft tissue and joint pathologies affecting the lower extremity. This article reviews the normal sonographic appearance of muscles, tendons, ligaments, nerves, bone, and cartilage. The ultrasound imaging appearance of various pathologic conditions affecting the hip, thigh, knee, lower leg, ankle,and foot are illustrated. The advantages of ultrasonography are highlighted.

Intra-articular treatment of hip osteoarthritis: a randomized trial of hyaluronic acid, corticosteroid, and isotonic saline

OBJECTIVE

Hyaluronic acid (HA) and corticosteroids are both widely used for intra-articular treatment of knee osteoarthritis (OA). We examined the effect of both drugs in intra-articular treatment for hip OA.

METHODS

One hundred and one patients with hip OA were included in a prospective double blind study, using a randomized controlled trial with a three-armed parallel-group design. Three ultrasound-guided, intra-articular injections were given at 14 days interval. The primary outcome measure was 'pain on walking', registered on a visual analogue scale (VAS). Evaluation was performed at baseline and after 14, 28 and 90 days. The study adhered to the Consolidated Standards of Reporting Trials. All analyses were based on intention-to-treat analyses, and used 'mixed-procedures' with the baseline-observation as covariate.

RESULTS

There were no significant interactions with respect to Treatment x Time for any of the analyzed outcome measures. There was a significant treatment effect for 'pain on walking' (P=0.044) due to a significant improvement following corticosteroid compared to saline with an effect-size of 0.6 (95% confidence interval: 0.1-1.1, P=0.021). By contrast, HA compared to saline had an effect size of 0.4 (-0.1 to 0.9; P=0.13). The peak-effect was obtained after 2 weeks. There was no difference between the treatment groups at endpoint. No significant side effects of the injections were observed.

CONCLUSIONS

Patients treated with corticosteroids experienced significant improvement during the 3 months of intervention, with an effect size indicating a moderate clinical effect. Although a similar significant result following treatment with HA could not be shown, the effect size indicated a small clinical improvement. A higher number of patients in future HA studies would serve to clarify this point.

Gluteal injection site granulomas: false positive finding on FDG-PET in patients with non-small cell lung cancer

Positron-emission-tomography (PET) with fludeoxyglucose F-18 ([(18)F] fluoro-2-deoxy-D-glucose, FDG) has become an established imaging modality in patients with lung cancer for mediastinal lymph node staging and the detection of extrathoracic metastases. However, tracer accumulations are not limited to malignant tissue but are also found in muscles and benign inflammatory processes. We report on two patients with lung cancer in whom FDG-PET revealed suspicious tracer accumulations in the buttock. Ultrasound (US) revealed a hyperechogenic nodule with poorly defined margins in both patients. On specific inquiry both patients reported on repeated "intramuscular" gluteal injections. Histology after US guided biopsy showed an accumulation of macrophages within fibrous tissue, compatible with injection site granulomas. The reported cases underline that (18)F-FDG may accumulate in benign, ancillary processes that have to be distinguished from distant metastases. Tracer accumulation in the buttocks may be highly suggestive of injection site granulomas, especially if the patient reports on "intramuscular" injections. In this setting, US is a widely available modality to distinguish metastasis from adipose tissue necrosis.